1. Field of the Invention
This invention generally relates to handling of objects, in particular easily damageable objects such as eggs and fruits (apples, peaches, and so on). It more specifically relates to an apparatus for shifting such objects from an upper conveyor to each of containers successively transferred by a lower conveyor.
2. Description of the Prior Art
In automated handling of eggs for example, it is usual to employ a shifting apparatus which is used to shift, at each time, a predetermined number of eggs from an upper conveyor into each of containers (plastic or paper packages) successively transferred on a lower conveyor. Obviously, eggs are easily damageable, so that care must be taken not to allow the eggs to come into contact with each other during handling.
As is well known, egg containers have rows of constantly spaced seating recesses. A typical shifting apparatus for transferring eggs into such a container includes a row (or rows) of egg holders which receive eggs in a row (or rows) from the upper conveyor and discharge them onto each row (or corresponding rows) of seating recesses of the container. Such a shifting apparatus is disclosed for example in Japanese Patent Publication No. 46-4778 and Japanese Patent Application Laid-open No. 60-110618.
Naturally, the pitch or distance between each two adjacent seating recesses of egg containers should preferably be as small as possible to increase the number of eggs to be packed into each container. However, this gives rise to a problem that eggs must be arranged in a row at correspondingly small spacing during handling thereof before shifting into the container, so that the eggs are more likely to come into contact with each other with resultant damaging or breakage of some eggs.
The typical prior art shifting apparatus described above is designed to receive eggs in a row (or rows) at constant spacing and to discharge them into each of containers at the same spacing as received from the upper conveyor. Thus, the prior art shifting apparatus has a disadvantage that eggs are likely to be damaged if the eggs are to be densely packed.
On the other hand, there are various specifications for egg containers according to various sizes of eggs to be packed. Further, the egg packing pitch of containers even for identically sized eggs may differ slightly depending for example on container manufacturers.
The holders of the typical prior art shifting apparatus are arranged at fixed spacing. Thus, the shifting apparatus is applicable only to containers of a predetermined specification. Although it is possible to incorporate an adjusting mechanism to change the spacing between the holders, such an adjusting mechanism usually requires complicated adjusting operation.